<!DOCTYPE html>
<html reftest-async-scroll
      reftest-displayport-x="0" reftest-displayport-y="0"
      reftest-displayport-w="800" reftest-displayport-h="2000"
      reftest-async-scroll-x="0" reftest-async-scroll-y="100">
<style>

body {
  margin: 0;
  overflow: hidden;
  height: 4000px;
}

.opacity {
  opacity: 0.8;
}

.box {
  left: 0;
  top: 200px;
  width: 200px;
  height: 200px;
}

.absolute {
  position: absolute;
  background: green;
}

.fixed {
  position: fixed;
  background: blue;
}

</style>

<div class="opacity">
  <div class="box absolute"></div>
  <div class="box fixed"></div>
</div>
